“Like clockwork, rumors of a cheaper iPhone are back,” my colleague Jared Newman wrote on Monday. Jared was reporting on the latest flurry of speculation that Apple is working on a low-cost iPhone that’s designed to broaden the iPhone’s appeal by making it more affordable. He’s skeptical that it amounts to anything.

As well he should be. Apple pundits love to work under the assumption that Apple must be developing a bargain-basement iPhone — and they most often think that the phone in question is less expensive because it’s smaller than the current model. This theoretical budget mini-iPhone is often called the “iPhone Nano,” an idea that’s so irresistible that it dates back at least to January 10, 2007, the day after the first iPhone was announced.

Why do these rumors keep resurfacing? Usually, it’s because of alleged evidence from the Asian supply chain that provides Apple with phone components, a notoriously shaky way to figure out what’s on the way. And the analysts who cover Apple have a weird predilection to conflate their own theories and desires with fact, leading some of them to breathlessly conclude — year after year — that the iPhone Nano is about to arrive. Mostly, it seems, because they think it would be a swell idea.

The scuttlebutt: Apple is about to announce a smaller iPhone with 3G capability, which will be free with certain contracts

The evidence: unspecified sources had “confirmed a number of important details to the Guardian”

The outcome: Apple did announce a 3G iPhone, and it was available for free in the U.K. on plans costing £45 and above. It wasn’t, however, smaller. In fact, it was just a skosh larger than its predecessor

The scuttlebutt: “as soon as Monday,” Apple will announce an iPhone for either $99 or $149, down from $199

The evidence: information from “people familiar with the initiative,” and Morgan Stanley analyst Kathryn Huberty

The outcome: hey, Apple did announce a $99 iPhone! But not on the following Monday. It didn’t slash prices until a year later, and when it did, it did so by knocking the year-old iPhone 3GS down to that price

The scuttlebutt: in the third quarter of 2010, Apple will release a worldphone version of the iPhone, compatible with both GSM and CDMA networks, which will have a “significantly smaller” 2.8″ screen

The evidence: a report from research firm OTR Global

The outcome: Apple did release an iPhone for Verizon. But it wasn’t a worldphone and it didn’t arrive until February, 2011. And it had a 3.5″ screen, not a 2.8″ one — just like every other iPhone before and after

The scuttlebutt: Apple is working on both a bigger iPhone and a smaller iPhone, so it has something for everybody from entry-level to high-end consumers — and they might ship sooner than Apple’s normal refresh cycle

The evidence: supply-chain checks by analyst Shaw Wu, the guy who started predicting a cheaper iPhone before the first iPhone went on sale

The outcome: as of April 23, 2012 — let’s see, it’s 6:03pm my time — Apple still only sells the iPhone in one size, although it does offer three models (the 4S, the 4 and the 3GS)

The scuttlebutt: Apple is working on an iPhone that’s one-third smaller than the current model, with no home button; it’s designed to sell for $200 without a carrier subsidy, might be out by midyear and is intended to help the company do battle with Google’s Android

The evidence: reports from “people who have been briefed on the plans”

The outcome: no such phone has been announced yet (and to be fair to Bloomberg’s reporters, they note that it might be delayed or canceled)

The scuttlebutt: Apple is working on an inexpensive iPhone for cost-conscious customers; it could arrive along with the next-generation iPhone later this year

The evidence: supply-chain rumors as reported by the China Times

The outcome: um, it’s still April 23 as I write this, so let’s give this one more time

My head is spinning from all these imaginary details on a non-product, although it’s certainly possible that some of these articles report on actual prototypes that Apple has toyed with and rejected. But you’d think by now that everyone involved would have figured out that glimmery hints of the iPhone Nano’s possible existence do not amount to solid evidence that it’s about to be announced.

All those analysts and other rumormongers are right: it makes a lot of sense for the iPhone to get more affordable. It’s just that their theories about how Apple’s going to accomplish that have been consistently misguided. Even though there’s nothing top-secret about the company’s cost-cutting strategy to date.

Which is why, if Apple ever does release an iPhone that’s been radically rethought with a lower pricetag in mind, it won’t be impressive that Apple-watchers predicted that it was on the way. Instead, as with an awful lot of professional Apple analysis, it’ll be embarrassing: how could so many experts be so wrong for so long?